Hillary Clinton and Donald Trump are two of the most polarizing presidential candidates in modern history. Veteran Frontline filmmaker Michael Kirk goes beyond the headlines to investigate what has shaped these two candidates, where they came from, how they lead and why they want one of the most difficult jobs imaginable.

Reporting from Jordan, Iraq, Saudi Arabia, Syria and Turkey, Frontline correspondent Martin Smith examines the successes, failures and challenges of the fight against ISIS, as the terror group loses ground in the region but strikes out abroad.

As Europe reels from a terror onslaught, top security officials describe their struggle to contain the unprecedented threat revealed by attacks in France and Belgium.

The first-person stories of refugees and migrants fleeing war, persecution and hardship — drawing on footage filmed bythe families themselves as they leave their homes on dangerous journeys in search of safety and refuge in Europe.

Frontline examines the key moments that shaped President-elect Donald Trump. Interviews drawn from The Choice 2016 with advisors, business associates and biographers reveal how Trump transformed himself from real estate developer to reality TV star to president.

Ahead of Donald Trump's inauguration, "Divided States of America" looks back at events during President Barack Obama's years in office that revealed deep divisions in our country. The documentary offers an in-depth view of the partisan gridlock in Washington, the rise of populist anger on both sides of the aisle, and the racial tensions that erupted throughout the country.

Ahead of Donald Trump's inauguration, "Divided States of America" looks back at events during President Barack Obama's years in office that revealed deep divisions in our country. The documentary offers an in-depth view of the partisan gridlock in Washington, the rise of populist anger on both sides of the aisle, and the racial tensions that erupted throughout the country.

An investigation of how Donald Trump defied expectations to win the presidency -- and what it suggests about how he will govern.

Battle for Iraq: Reporter Ghaith Abdul-Ahad goes inside the battle against ISIS for control of the city of Mosul. Hunting ISIS: a dramatic report on an Iraqi unit at the center of the fight.

Out of Gitmo: The dramatic story of a Gitmo detainee released from the controversial U.S. prison after more than a decade. With NPR, a report on the struggle over freeing prisoners once deemed international terrorists. Forever Prison: a collaboration with Retro Report exploring the untold history of the Guantanamo Bay prison.

FRONTLINE investigates allegations of abuse of Sunni Muslim civilians by powerful Shia militias.

Inside one state’s ambitious attempt to decrease its use of solitary — and what happens when prisoners who have spent considerable time in isolation try to integrate back into society.

Best-selling author and lifelong fisherman Paul Greenberg spends a year eating fish at breakfast, lunch and dinner to help answer the question: “What fish should I eat that’s good for me and good for the planet?”

Frontline investigates the fight over the fate of juveniles serving life in prison for murder, following a landmark Supreme Court ruling. The film examines the impact of the order to re-evaluate thousands of juvenile murder cases and follows two of the first convicts to be released.

An investigation with NPR into the billions spent on housing low-income people, and why so few get the help they need. The film examines the politics, profits and problems of an affordable housing system in crisis.

Frontline investigates how the Bundy family's fight against the government invigorated armed militias and "patriot" groups. The film goes inside the family's standoffs over public land in the West, and examines how groups aligned with them have grown to levels not seen in decades.

The team behind "The Choice 2016" and "Divided States of America" tells the inside story of Trump adviser Stephen Bannon and his war with Washington, with White House rivals and with Islam. Frontline explores Bannon's personal crusade to dramatically transform America, and his role in the power struggles and policy clashes within the Trump administration.

With unique access, Frontline and The New York Times go inside an effort to change the way parole works in Connecticut and reduce the number of people returning to prison. The film follows four former inmates as they try to find work, stay sober and keep out of trouble while navigating their first year on parole.

Who killed Kim Jong-un’s half brother, Kim Jong-nam? What does the murder reveal about the North Korean leader and his regime? As nuclear tensions grow, Frontline examines claims that Kim Jong-un ordered the assassination of his half brother, and sheds light on his broader intentions.

How did Scott Pruitt go from fighting the EPA to running it and rolling back years of environmental protections? With access to key players behind his rise, and former EPA officials, Frontline provides an inside look at the ascent of the anti-regulatory movement in America.